LM3431AQ National Semiconductor, LM3431AQ Datasheet
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LM3431AQ
Manufacturer Part Number
LM3431AQ
Description
3-Channel Constant Current LED Driver
Manufacturer
National Semiconductor
Datasheet
1.LM3431AQ.pdf
(24 pages)
© 2009 National Semiconductor Corporation
3-Channel Constant Current LED Driver with Integrated
Boost Controller
General Description
The LM3431 is a 3-channel linear current controller combined
with a boost switching controller ideal for driving LED back-
light panels in space critical applications. The LM3431 drives
3 external NPN transistors or MOSFETs to deliver high ac-
curacy constant current to 3 LED strings. Output current is
adjustable to drive strings in excess of 200 mA. The LM3431
can be expanded to drive as many as 6 LED strings.
The boost controller drives an external NFET switch for step-
up regulation from input voltages between 5V and 36V. The
LM3431 features LED cathode feedback to minimize regula-
tor headroom and optimize efficiency.
A DIM input pin controls LED brightness from analog or digital
control signals. Dimming frequencies up to 25 kHz are pos-
sible with a contrast ratio of 100:1. Contrast ratios greater than
1000:1 are possible at lower dimming frequencies.
The LM3431 eliminates audible noise problems by maintain-
ing constant output voltage regulation during LED dimming.
Additional features include LED short and open protection,
fault delay/error flag, cycle by cycle current limit, and thermal
shutdown for both the IC and LED array. The enhanced
LM3431A features reduced offset voltge for higher accuracy
LED current.
Typical Application Circuit
LM3431/LM3431A/LM3431Q/
300411
LM3431AQ
Features
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Applications
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LM3431Q/LM3431AQ are Automotive Grade products
that are AEC-Q100 grade 1 qualified (-40°C to 125°C
operating junction temperature)
3-channel programmable LED current
High accuracy linear current regulation
Analog and digital PWM dimming control
Up to 25kHz dimming frequency
>100:1 contrast ratio
Integrated Boost controller
5V-36V input voltage range
Adjustable switching frequency up to 1MHz
LED short and open protection
Selectable fault shutdown or automatic restart
Programmable fault delay
Programmable cycle by cycle current limit
Output Over Voltage Protection
No Audible Noise
Enable pin
LED Over-Temperature shutdown input
Thermal Shutdown
TSSOP-28 exposed pad package
Automotive Infotainment Displays
Small to Medium Format Displays
www.DataSheet4U.com
March 10, 2009
www.national.com
30041101